In assessing a person's skin from cosmetic and health perspectives, the amount of photodamage due, e.g., to sun exposure is an important factor. High exposure levels have been correlated to increased risk of skin cancer due to U-V radiation—induced cell mutations. Sun exposure also has detrimental cosmetic effects on the skin, e.g., the skin loses elasticity and color homogeneity, as evidenced by “age spots” or solar lentigenes. It is known that photodamage is associated with/indicated by internal changes to the skin which underlie the observed external skin attributes. One of these internal changes occurs in the superficial (papillary) dermis. More particularly, as persons age and their cumulative exposure to the sun increases, elastotic material accumulates in the superficial dermis, in the form of abnormally clumped elastic fibers accompanied by deformed collagen fibers.
Visualization and physical examination of a person's skin by a dermatologist and/or histological examination of a skin sample can yield information on the degree of photodamage, however, such techniques require expensive professional services are inconvenient, sometimes unpleasant and frequently do not result in a comprehensive, quantified measure of photodamage of a large area of the skin, such as the face, relative to a norm.
Various imaging systems have been proposed that photographically capture images of a person's face for analysis of the health and aesthetic appearance of the skin. Different images, e.g., captured at different times or under different lighting conditions, e.g., using different illumination and filtration frequencies, can be compared to one another to gain insight into the condition of the skin, e.g., at different times, such as before and after treatment, in order to ascertain trends in the condition of the skin. This was typically done by human operators inspecting the photographs to ascertain changes between them, based on color, texture, etc.
While photographic skin imaging and analysis by human inspection is quite useful, it remains an objective in the art to conduct such analyses more insightfully without dependence upon professional evaluation and Judgment and in a more objective and reproducible manner.